Each post has breadcrumb navigation like:
Home > Category Name > Post Name
If category has no index, I should add a rel="nofollow" to the link towards the category.
I mean there is no need to parse link juices for a cateogry which will not be indexed. This way, the posts from my category will pass link juices only to my index page. Right?

What If I use javascript to make the link? Than the html will just feature a html text and not an actual link... the link would be loaded with javascript and rel nofloow
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webmastersSep 15 '11 at 16:01

If the link is created with JavaScript it will not be subject to nofollow and it will not be found by the search engines (if it is done correctly).
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John Conde♦Sep 15 '11 at 19:08

John, Actually Google does run a certain amount of your JavaScript, so I'm not so sure that would be 100% accurate as of 2014. They run the JavaScript to see what/how you change the content of the page because they count visible links and do not count (or rather possibly penalize) invisible links.
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Alexis WilkeJul 28 '14 at 20:49